The present invention generally relates to a device adapted to be used in a medical procedure. More particularly, the present invention pertains to a wire for removing an intravascular foreign body (such as embolus in a vessel) and a medical instrument.
The vital statistics of population published by the Ministry of Health, Labor, and Welfare indicates that cancer dominates the cause of Japanese death, while heart disease and cerebral apoplexy represent the second and third leading causes of Japanese death. The increasing deaths and sequelae due to cerebral apoplexy urgently demand to establish its therapeutic method.
A recent development in therapy of cerebral apoplexy is thrombolysis involving use of a thrombolitic agent to cure brain infarction in its acute phase. This therapy is effective, but its effectiveness is limited. That is, the thrombolitic agent takes a long time for thrombolysis or produces smaller thrombi that scatter to form new emboli. In addition, it has been found that some emboli are insoluble by treatment with a thrombolitic agent.
It has been proved in the U.S. and Europe that the probability to save lives and reduce sequelae would be high if the blood flow is resumed within 3 hours after the onset of cerebral apoplexy. Thus, there is a strong interest in developing a new medical instrument that can be inserted into a cerebral vessel to remove the thrombus directly. An example of such a medical instrument is a wire for removing an intravascular foreign body which is disclosed in Japanese Patent Laid-open No. 2004-16668.
The wire for removing an intravascular foreign body consists of a wire proper, two branch wires (which branch out from the wire proper), and a plurality of filaments connecting the branch wires. The branch wires and the filaments form a space in which an intravascular foreign body is captured.
The disadvantage of this disclosed wire for removing an intravascular foreign body is that, depending on the size, the wire is sometimes not able to capture an intravascular foreign body.
For example, if the intravascular foreign body is smaller than the space in which it is to be captured, the intravascular foreign body might slip through the gap between the filaments. In such a case, it would be necessary to exchange the wire for removing an intravascular foreign body with a different that matches the size of the foreign body to be captured. This is troublesome.